Method and telecommunications node for controlling an attach state of a user equipment

ABSTRACT

The invention relates to a method and telecommunications node for controlling an attach state of a user equipment in an attach control node of a telecommunications system further comprising a subscriber database containing subscription data of the user equipment. The method comprises receiving authentication data in the attach control node if an authentication step is required. Following the authentication step, if any, receiving in a first transfer stage a first set of subscription data from the subscriber database and storing the first set of subscription data in the attach control node, wherein the first set of subscription data is insufficient for enabling establishing a communication session between the user equipment and the telecommunications system. If establishing a communication session is required between the user equipment and the telecommunications network, receiving in a second transfer stage following the first transfer stage a second set of subscription data from the subscriber database in the attach control node, and storing the second set of subscription data in the attach control node, wherein the combination of the first set of subscription data and the second set of subscription data is sufficient for enabling establishing a communication session between the user equipment and the telecommunications network.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a national stage entry of, and claimspriority to, PCT/EP2014/065071, filed on Jul. 15, 2014, which claimspriority to European Patent Application EP 13176452.4, filed in theEuropean Patent Office on Jul. 15, 2013, both of which are herebyincorporated in their entirety herein by reference.

FIELD OF THE INVENTION

The disclosure relates to a method and a telecommunications node fortransferring subscription data in a telecommunications system. Morespecifically, the disclosure relates to controlling the exchangesubscription data in a system comprising a subscriber database and anattach control node to which user equipment may connect.

BACKGROUND

Telecommunications networks that provide wireless access (e.g. GSM,UMTS, WiMax, LTE) have developed tremendously over the past years. Insuch networks, voice and data services can be provided to user equipmenthaving a high mobility, i.e. the communication devices are not bound toa particular location and are freely movable through the area covered bythe network. A gateway node of the telecommunications network enablesconnection to a further network, for example a network based on IP suchas the internet.

The availability of such a telecommunications network connected to thefurther network has resulted in demands for further services, includingservices that relate to so-called machine-to-machine (M2M)communications, also referred to as machine-type communications (MTC).The service requirements for MTC are currently being standardized in3GPP (see e.g. TS 22.368). MTC applications typically involve hundreds,thousands or millions of user equipment (MTC devices) which each act asa user equipment to the telecommunication network. Such MTC devices maybe stationary or non-stationary. An example involves the electronicreading of e.g. ‘smart’ electricity meters at the homes of a largecustomer base over the telecommunications network from a serverconnected to a further network. Other examples include sensors, meters,vending or coffee machines, car meters for route pricing applications,navigation equipment etc. that can be equipped with communicationmodules that allow exchanging information with other equipment, such asa data processing centre over the telecommunications network.

An important dimensioning parameter for control plane nodes in thewireless telecommunications networks is the number of simultaneouslyattached/registered user equipment.

Since MTC typically involves a very large number of MTC devices thatsend/receive only a low amount of user plane data, the use of controlplane resources needed for these MTC devices is high compared to theuser plane data that is normally the basis for pricing. The absorbedcapacity and costs associated with large numbers of MTC devices aretherefore high compared to the actual use and turnover. Solutions tomitigate the burden of keeping high amounts of MTC devices registered inthe network would be beneficial.

The issue of registering large numbers of MTC devices in thetelecommunications network has been recognized and discussed in various3GPP working groups. In a potential solution described in 3GPP TR23.888, an MTC device would not be registered in the telecommunicationsnetwork when it does not communicate. The MTC device will attach andconnect to the network when triggered from the network. The triggerinvolves enabling the MTC device to listen to a broadcast channel (e.g.a cell broadcast channel) while not being attached to the network.Triggers to the MTC device to establish communication are broadcastedover the broadcast channel. The MTC device(s) for which the broadcastedmessage/trigger is intended is (are) configured to recognize themessage. In this way, network resources associated with registering alarge number of MTC devices in the network are saved.

However, non-registration of the MTC devices in the telecommunicationsnetwork may be disadvantageous in certain cases. For example, thetransmission of a cell broadcast signal may be inefficient if only alimited number of MTC devices are distributed over a large number ofcells of the network and broadcast resources are wasted in view of thelimited number of MTC devices to be triggered.

SUMMARY

In view of the above, it is desirable to provide an improved method andtelecommunications node for transferring subscription data over anetwork that takes account of the issues identified above.

To that end, a method for controlling an attach state of a userequipment in an attach control node of a telecommunications systemfurther comprising a subscriber database containing subscription data ofthe user equipment is disclosed. If an authentication step is required,the attach control node receives authentication data. If authenticationis performed, the authentication data is normally received from anauthentication centre AuC or an AAA server. Such an authenticationcentre or server may be integrated with the subscriber database.

In a first transfer stage step following the authentication step, ifany, a first set of subscription data is received in the attach controlnode from the subscriber database. The first set of subscription data isstored in the attach control node. However, the first set ofsubscription data is insufficient for enabling establishing acommunication session between the user equipment and thetelecommunications system. The first transfer stage step may betriggered by receiving an attach request from the user equipment at theattach control node.

Since the first set of subscription is insufficient for enablingestablishing a communication session between the user equipment and thetelecommunications network, if establishing a communication session isrequired, at least one second set of subscription data is received fromthe subscriber database in the attach control node during a secondtransfer stage step. The second transfer stage step is performed afterthe first transfer stage step. The second set of subscription data isstored in the attach control node. The combination of the first set ofsubscription data and the second set of subscription data is sufficientfor enabling establishing a communication session between the userequipment and the telecommunications network.

Moreover, a computer program product implemented on a computer-readablenon-transitory storage medium is disclosed, the computer program productbeing configured for, when run on a computer, executing the method stepsdisclosed herein.

Still further, a telecommunications node configured for use in atelecommunications system comprising a subscriber database containingsubscription data of a user equipment is disclosed. Thetelecommunications node is configured for receiving authentication data,if an authentication step is required, in the attach control node. Thetelecommunications node is also configured for, following theauthentication step, if any, a first set of subscription data from thesubscriber database in a first transfer stage step and storing the firstset of subscription data. The first set of subscription data isinsufficient for enabling establishing a communication session betweenthe user equipment and the telecommunications system. The attach controlnode may be configured to initiate the first transfer stage step inresponse to receiving an attach request from the user equipment at theattach control node.

If establishing a communication session is required between the userequipment and the telecommunications network, the telecommunicationsnode is configured for receiving in a second transfer stage, followingthe first transfer stage, at least one second set of subscription datafrom the subscriber database and storing the second set of subscriptiondata in the attach control node. The combination of the first set ofsubscription data and the second set of subscription data is sufficientfor enabling establishing a communication session between the userequipment and the telecommunications network.

Finally, a user equipment is disclosed that is configured for use withthe telecommunications node as described in the previous paragraph. Theuser equipment is configured for receiving and processing at least oneof a partial subscription data transfer indication indicative of storingonly the first set of subscription data in the telecommunications nodeand, if the user equipment is an LTE type user equipment, a non-bearerestablishment indication indicative of omitting establishment of adefault bearer on a radio path between the LTE type user equipment andthe telecommunications node prior to initiation of the second stagebeing insufficient for enabling establishment.

It is noted that the first transfer stage and the second transfer stagefor the subscription data may be distinguished by different transactionidentifiers.

By only storing in the attach control node the first set of subscriptiondata and omitting storing at least part of the set of subscription datarequired for establishing a communication session, a partial attachstate is obtained for the user equipment in the telecommunicationsnetwork. The partial attach state is defined by the content of the firstset of subscription data. The storage of the first set of subscriberdata in the attach node provides information about the cells where theuser devices are positioned, viz. those cells for which the particularattach node is responsible. However, since the first set of subscriberdata is not the complete set of subscriber data required for enablingthe full attach of the user equipment to the telecommunications system,resources are saved in the attach control node. This disclosed solutionprovides for a good balance between a better awareness in the network ofthe cell location of the user equipment and the saving of resources inthe attach node.

By defining the content of the first set of subscriber data, (other)benefits associated with having the defined content of the first set ofsubscriber data available in the attach control node are obtained. Forexample, the content of the first set of subscriber data may comprise aparameter known as the network access mode. The NAM is e.g. defined in3GPP TS 23.008. The NAM defines if the subscriber is registered to getaccess to the CS (non-GPRS/EPS network), to the PS (GPRS/EPS) network orto both networks. The NAM is permanent subscriber data stored in theHSS/HLR. By storing the NAM in the attach control node in response tothe attach request, the attach control node is informed to which networkthe MTC device gets access to.

Examples of subscription data fields of the second set include at leastone of the fields APN-OI Replacement, ODB for PS parameters, VPLMN LIPAAllowed Subscribed UE-AMBR and the APN configurations listed in 3GPP TS23.060, V. 11.3.0 in table 5 of Clause 13.1. 3GPP TS 23.060 is for 2G/3GPacket Switched, the equivalent for LTE (HSS) is 3GPP TS 23.401,V.12.0.0 table 5.7.1-1.

Another advantageous effect of the disclosed method andtelecommunications node is that the network operator is in controlwhether or not to allow a communication session with the user equipment.Only when the at least one second set of subscriber data is available atthe attach control node, a request by the user equipment for acommunication session can be allowed. By informing the user equipment ofthe partial attach state, the user equipment may even be instructed notto send such a request during the partial attach state.

It should be appreciated that the first and the at least one second setof subscription data may be predefined in advance or be selected upontransferring the subscription data to the attach control node or storingthe subscription data in the attach control node, e.g. depending on acondition.

The term subscriber data is used to designate all information associatedwith a subscription which is required for service provisions,identification, routing, communication session handling, GPRS modetransmission, charging, subscriber tracing, operation and maintenancepurposes. Some subscriber data are referred to as permanent subscriberdata, i.e. they can only be changed by administration means. Other dataare temporary subscriber data which may change as a result of normaloperation of the system. It is not necessary or required that allsubscriber data are transferred to the attach control node.

It should be appreciated that the communication session may be either adata session or a session involving establishment of a voice channel.

It should also be appreciated that some subscription data, such as theIMSI of the user equipment, that play a role in the attach controlstate, is also used during authentication. As disclosed, if anauthentication step is performed, subscription data present forauthentication purposes in the attach control node are not considered tobe part of the first set of subscription data.

It should be appreciated that during the first transfer stage, allsubscriber data may be transmitted in that step from the subscriptiondatabase to the attach control node. The attach control node only storesthe first set of subscriber data from the received subscriber data.

It should be appreciated that the second transfer stage not necessarilyfollows the first transfer stage, i.e. the second set of subscriber datais not stored in the attach control node. The user equipment may e.g.transmit a restricted set of data by other means, e.g. by using a shortmessage service or transmit a restricted set of data via the controlplane.

The establishment of a communication session between the user equipmentand the telecommunications session may comprise establishing a user dataplane communication session, e.g. a PDP context or an EPS bearer.

Finally, it should be appreciated that the term user equipment in thepresent disclosure may include devices with or without SIM/UICC.

In an embodiment of the method and telecommunications node, alternativesfor storing the first set of subscription data in the attach controlnode are disclosed.

In one alternative, a request is transmitted from the attach controlnode to the subscriber database, optionally in response to receiving anattach request from the user equipment at the attach control node, andreceiving only the first set of subscription data on the basis of apartial transfer indication associated with the user equipment in thesubscription database. In this embodiment, the control of transmittingonly first set of subscription data lies with the system containing thesubscription database, dependent on the setting of the partial transferindication.

In another alternative, a request is transmitted from the attach controlnode to the subscriber database, the request containing a partialtransfer indication. The partial transfer indication may originate fromthe attach control node, i.e. control of only transmitting the first setof subscriber data lies with the attach control node. For example, ifthe attach control node determines that it only has limited resourcesavailable, it may decide to transmit the partial transfer indication tothe subscriber database system. In a variant, the attach control nodereceives an attach request from the user equipment, wherein the attachrequest from the user equipment already contains a partial transferindication. The attach control node may either forward the partialtransfer indication originating from the user equipment or provide foran alternative partial transfer indication in response to the partialtransfer indication received from the user equipment. In this variant,the user equipment controls the transmission of only the first set ofthe subscriber data as may e.g. be advantageous for a user equipment notrequiring a communication session any time soon. The attach control nodemay be configured to overrule the transfer indication of the userequipment. In one variant, a partial transfer indication may be receivedfrom the user equipment, but the attach control node may decide that afull attach with all subscription data is desired or required. Inanother variant, the attach control node may receive a conventionalattach request from the user equipment but decide to only allow apartial attach (for example because of limited available resources) andthus transmit a request with a partial transfer indication to thesubscriber database.

Yet another alternative comprises receiving a complete set of subscriberdata from the subscriber database and storing only a first set ofsubscriber data from the received subscriber data in response to apartial attach state indication in the attach control node. In thisalternative, the decision to store only the first set of subscriber datalies with the attach control node as well.

In another embodiment, the transfer of the at least one second set ofsubscription data is stored in the attach control node as a result offulfillment of a precondition.

In one alternative, the second set of subscription data is stored inresponse to a data availability indication in the telecommunicationssystem indicating the availability of data for the user equipment. Inthis alternative, the at least one second set of subscription data istransmitted when data is to be sent to the user equipment, so that thecommunication session relevant subscription data need to be with theattach control node.

In another alternative, the second set of subscription data may bedesired with the attach control node in response to a resourceavailability indication received from the attach control node at thesubscription database indicating the availability of resources forcontaining the second set of subscription data in the attach controlnode. In this case, a communication session may be established morequickly.

In yet another alternative, the second set of subscription data may bestored with the attach control node at a predefined time or within apredefined time interval. This case is advantageous if information isavailable within the telecommunications system when a user equipmentdesires to establish a connection with the telecommunications system.Such information may e.g. be available from a contract between theoperator of the telecommunications system and the operator of the userequipment. As an example, such a contract may determine the time atwhich or the time interval during which the user equipment will or isallowed to transmit data.

In an embodiment of the method and telecommunications node, the at leastone second set of subscription data from the combination of the firstand second set of subscription data is deleted after a precondition hasbeen fulfilled. The first set of subscription data may remain in theattach control node. The precondition may relate to the expiry of atimer, the detection of the end of the communication session for theuser equipment and/or to the detection of limited availability of (free)resources in the attach control node.

Resources may also be saved on the radio path between the user equipmentand the telecommunications system, particularly for LTEtelecommunications system. Prior to the initiation of the secondtransfer stage, establishment of a default bearer is omitted. Thedefault bearer may be established after initiation of the secondtransfer stage since the transfer of the second set of subscription datamay be initiated in order to transfer data to or from the userequipment, requiring the presence of the default bearer. The userequipment may be informed of the non-establishment of the default bearer(either explicit or implicit) and should be configured not to processthe lack of a default bearer as an unsuccessful attach.

It is noted that the invention relates to all possible combinations offeatures recited in the claims. Thus, all features and advantages of thefirst aspect likewise apply to the second and third aspects,respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the invention will be explained in greater detail byreference to exemplary embodiments shown in the drawings, in which:

FIG. 1 is a schematic illustration of a telecommunications system;

FIGS. 2A-2C are prior art sequence diagrams illustrating steps inestablishing a communication session for a user equipment in thetelecommunications system of FIG. 1;

FIG. 3 is a schematic system block diagram illustrating a userequipment, an attach control node and a subscriber data system accordingto an embodiment of the invention;

FIG. 4 is a sequence diagram illustrating steps according to thedisclosed method;

FIGS. 5A-5D are sequence diagrams for a 2G/3G telecommunications systemillustrating various embodiments of establishing a partial attach statefor a UE;

FIG. 6 is a sequence diagram for a 2G/3G telecommunications systemillustrating the effect of the partial attach state of the attachcontrol node on a PDP context request from the UE;

FIGS. 7A-7C are sequence diagrams for a 2G/3G telecommunications systemillustrating network-initiated data transmission according to the priorart (FIG. 7A) and according to embodiments of the invention (FIGS. 7Band 7C);

FIG. 8 is a schematic illustration of an attach control node containinga storage with a non-overwritable part A and an overwritable part B;

FIGS. 9A and 9B are sequence diagrams for a 2G/3G telecommunicationssystem illustrating return to a partial detach state;

FIGS. 10A-10C are sequence diagrams for an LTE/EPS telecommunicationssystem illustrating various embodiments of establishing a partial attachstate for a UE;

FIGS. 11A and 11B are sequence diagrams for an LTE/EPStelecommunications system illustrating embodiments for a transition froma partial attach to a complete attach state for a UE; and

FIGS. 12A and 12B are sequence diagrams for an LTE/EPStelecommunications system illustrating embodiments for a transition froma complete attach state back to a partial attach state for a UE.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic illustration of a telecommunications system 1.The telecommunications system 1 enables communication sessions betweenan application server 2 and a user equipment 3 over a data network 4,wherein access of the user equipment 3 to the telecommunications system1 is wireless.

In the telecommunications system of FIG. 1, three generations oftelecommunications networks are schematically depicted together forpurposes of brevity. A more detailed description of the architecture andoverview can be found in 3GPP TS 23.002 and 3GPP TS 23.060, 3GPP TS23.401 and 3GPP TS 23.402, which are included in the present applicationby reference in its entirety.

The lower branch of FIG. 1 represents a GPRS or UMTS telecommunicationssystem comprising a Gateway GPRS Support Node (GGSN), a Serving GPRSSupport Node (SGSN) and a Radio Access Network (GERAN or UTRAN). For aGSM/EDGE radio access network (GERAN), the wireless access networkcomprises a Base Station Controller (BSC) connected to a plurality ofBase Station Transceivers (BTSs), both not shown. For a UMTS radioaccess network (UTRAN), the wireless access network comprises a RadioNetwork Controller (RNC) connected to a plurality of NodeBs, also notshown. The SGSN is conventionally connected to a Home Location Register(HLR) that contains subscription data of the user equipment 3.

The upper branch in FIG. 1 represents a next generationtelecommunications system, commonly indicated as Long Term Evolution(LTE) or Evolved Packet System (EPS). Such a system comprises a PDNGateway (P-GW) and a Serving Gateway (S-GW). The E-UTRAN of the EPScomprises evolved NodeBs (eNodeBs or eNBs) providing wireless access fora user equipment 3 that is connect-connected to the S-GW via a packetnetwork. The S-GW is connected to a Mobility Management Entity MME forsignalling purposes which is in turn connected to a Home SubscriberServer HSS. The HSS includes a subscription profile repositorycontaining subscription data for the user equipment 3.

The user equipment 3 comprises an MTC device and the application server2 may be an MTC server serving a large number of MTC devices 3.

FIG. 2A is a prior art sequence diagram illustrating initial steps inestablishing a communication session for a user equipment 3 in the lowerbranch of the telecommunications system 1 of FIG. 1 (the attach phase).In particular, FIG. 2A illustrates known steps of a packet-switchedattach procedure in a 2G/3G network.

In a first step (i), the UE 3 transmits an Attach request to thetelecommunications system 1, which Attach request is processed by theSGSN. In a subsequent step (ii), authentication of the UE 3 is performedinvolving the HLR.

Then, in step (iii), the SGSN transmits an Update location message tothe HLR which causes the HLR in step (iv) to transmit the full batchsubscriber data associated with the UE 3 user equipment 3 having sentthe Attach request in step (i). The specification of the “InsertSubscriber Data” message is e.g. defined in TS 29.002 clause 8.8.1 en TS29.272 clause 5.2.2.1.

After step (iv), the SGSN stores all the information necessary forcompleting the attach procedure such that a communication session can beestablished subsequently by establishing a PDP context for the UE 3.

In steps (v) and (vi), the receipt of the subscriber data isacknowledged.

It should be noted that, as a result of the data size of the subscriberdata (the data unit size of the underlying layer may be insufficient tocarry all the subscriber data in one data unit), steps (iv) and (v) maybe repeated a number of times, to transfer all the data to the SGSN.However, this transfer is performed under the same transactionidentifier, i.e. there is only one transfer stage.

Finally, in step (vii), the UE 3 is informed that the Attach requestfrom step (i) has been accepted via an Attach accept message.

After having received the Attach accept message, the UE 3 is able torequest activation of a PDP context procedure in a manner known in theart and as illustrated in steps (viii)-(xi) in FIG. 2B.

FIG. 2C is a prior art sequence diagram illustrating initial steps inestablishing a communication session for a user equipment 3 in the upperbranch of the telecommunications system 1 of FIG. 1. In particular, FIG.2C illustrates known steps of a packet-switched attach procedure in a 4GLTE/EPS network.

In this telecommunications system 1, similar steps are performed for theUE 3 to get attached to the telecommunications system 1 now using theMME and HSS. However, in order to provide for an always on type ofservice experience, a default bearer is established during the attachprocedure as shown in FIG. 2C between the UE and the S-GW and P-GW.

FIG. 3 is a schematic system block diagram illustrating a user equipmentUE 3, an attach control node 10 and a subscriber data system 11 (asubscriber database) according to an embodiment of the invention. In theblock diagrams, some components for performing the disclosed method areschematically illustrated. It should be noted that these components maybe implemented in hardware, software or in a hybrid fashion.

The UE 3, the attach control node 10 and the subscriber data system 11each contain at least a processor uP for executing actions, a controllerCTRL for controlling actions by the processor uP and one or more formsof storage (not shown) for storing computer programs and (intermediate)processing results. The attach control node 10 contains a storage 12 forstoring content, such as subscription data, received from the subscriberdata system 11. Obviously, each of the UE 3, the attach control node 10and the subscriber data system 11 comprises one or more communicationinterfaces (Tx/Rx) as known in the art for communicating with otherdevices in the telecommunications system or with the UE 3.

The UE 3 may be an MTC device. An example of such an MTC device involvesa ‘smart’ electricity meter at the home of a customer of a largecustomer base. The smart electricity meter may e.g. have data to reportto the application server 2 or may need a software update. Otherexamples of MTC devices include sensors, meters, vending or coffeemachines, car meters for route pricing applications, navigationequipment etc. that can be equipped with communication modules thatallow exchanging information with other equipment, such as theapplication server 2.

The attach control node 10 is configured for controlling attachment ofthe UE 3 to the telecommunications system 1. Examples of such attachcontrol nodes 10 comprise an SGSN (as briefly described with referenceto FIG. 2A), an MME (as briefly described with reference to FIG. 2C) andan MSC server (not depicted, comparable to FIG. 2A since the MSC serveris comparable to SGSN in this case).

The subscriber data system 11 stores the subscription data for all UE's3 that have a contract with the network provider. Examples of suchsubscriber data systems include an HLR (as briefly described withreference to FIGS. 1 and 2A) and an HSS (as briefly described withreference to FIGS. 1 and 2C).

FIG. 4 is a sequence diagram illustrating the basic steps of thedisclosed method. In a first step A, subscription data is transmittedfrom the subscriber data system 11 to the attach control node 10. Theattach control node 10 stores a first set of subscription datainsufficient for enabling establishment of a communication sessionbetween the user equipment and the telecommunications system. The firststep A may be triggered by receiving an attach request from the UE 3 atthe attach control node 10 followed by an indication (not shown) fromthe attach control node 10 to the subscriber database 11.

The storage of the first set of subscriber data results in a partialattach state for the user equipment UE 3 in the telecommunicationssystem. The partial attach state is defined by the content of the firstset of subscriber data.

Only in response to another trigger, subscriber data is transferred fromthe subscriber data system to the attach control node such that acomplete attach of the user equipment to the telecommunications systemis possible (step B). Then, the attach control node is in the same stateas after step (iv) in FIGS. 2A and 2C (without the default bearer)depicting the prior art.

Since the first set of subscriber data is not the complete set ofsubscriber data required for enabling the full attach of the userequipment to the telecommunications system, resources are saved in theattach control node 10 in the partial attach state. On the other hand,by defining the content of the first set of subscriber data, benefitsassociated with having the defined content of the first set ofsubscriber data available in the attach control node are obtained. Thecontent of the first set of subscriber data may enable individuallyaddressing user equipment (e.g. triggering a user equipment with an SMSmessage).

The content of the first set of subscriber data may comprise a parameterknown as the network access mode. The NAM is e.g. defined in 3GPP TS23.008. The NAM defines if the subscriber is registered to get access tothe CS network (non-GPRS/EPS network), to the PS network (GPRS/EPSnetwork) or to both networks. The NAM is permanent subscriber datastored in the HSS/HLR. By registering the NAM in the attach control nodein response to the attach request, the attach control node is informedto which network the user equipment gets access to.

Examples of subscription data fields of the second set include at leastone of the fields APN-OI Replacement, ODB for PS parameters, VPLMN LIPAAllowed Subscribed UE-AMBR and the APN configurations listed in 3GPP TS23.060, V. 11.3.0 in table 5 of Clause 13.1. 3GPP TS 23.060 is for 2G/3GPacket Switched, the equivalent for LTE (HSS) is 3GPP TS 23.401,V.12.0.0 table 5.7.1-1.

In the disclosed method, a purpose-related distinction may have beenmade with respect to the subscription data. A first set I ofsubscription data may be defined that as such is insufficient forenabling establishment of a communication session between the UE 3 andthe telecommunications system 1. A first set only containing the NAM ismentioned above is an example. In other words, the first set I ofsubscription data would not allow establishment of a PDP context, e.g.the messages (ix)-(xi) of FIG. 2B would not be transmitted if only thefirst set of subscription data would be available at the SGSN.

A second set II of subscription data is defined that, in combinationwith the first set I of subscription data would be sufficient forenabling activation of a communication session between the UE 3 and thetelecommunications system 1. In other words, if the attach control node10 would have available the first and second set of subscription data, aPDP context activation would be successful in the same manner asdepicted in FIG. 2B.

The second set II of subscription data would e.g. comprise communicationsession management subscription data, e.g. data related to an accesspoint name APN that is allowed by the subscription (subscribed APN(s)),e.g. APN configurations.

Below, a table is provided with examples of fields that may be part ofthe second set II of subscription data.

Field Description APN-OI Replacement Indicates the domain name toreplace the APN-OI when constructing the GGSN/PDN GW FQDN upon which toperform a DNS resolution. This replacement applies for all the APNs inthe subscriber's profile. See TS 23.003 [4] clause 9.1.2 for moreinformation on the format of domain names that are allowed in thisfield. ODB for PS parameters Indicates that the status of the operatordetermined barring for packet oriented services. VPLMN LIPA AllowedSpecifies per PLMN whether the UE is allowed to use LIPA. SubscribedUE-AMBR The Maximum Aggregated uplink and downlink MBRs to be sharedacross all Non-GBR PDP contexts according to the subscription of theuser. Each subscription profile may also contain one or more APNconfigurations: PDP/EPS Bearer Context Index of the PDP/EPS Bearercontext. Identifier PDP Type PDP type, e.g. PPP or IP (IPv4, IPv6,IPv4v6). PDP Address PDP address, e.g., an IP address. This field shallbe empty if dynamic addressing is allowed. APN-OI Replacement APN levelAPN-OI Replacement which has the same role as the UE level APN-OIReplacement but with higher priority than UE level APN-OI Replacement.This is an optional parameter. When available, it shall be used toconstruct the GGSN/PDN GW FQDN instead of UE level APNOI Replacement.See TS 23.003 [4] clause 9.1.2 for more information on the format ofdomain names that are allowed in this field. Access Point Name A labelaccording to DNS naming conventions describing the access point to thepacket data network. For S4-SGSN the APN to be used as default APN isindicated. SIPTO permissions Indicates whether the traffic associatedwith this APN is allowed or prohibited for SIPTO LIPA permissionsIndicates whether the PDN can be accessed via Local IP Access. Possiblevalues are: LIPA-prohibited, LIPA-only and LIPA-conditional. QoS ProfileSubscribed The quality of service profile subscribed. QoS ProfileSubscribed is the default level if a particular QoS profile is notrequested.. QoS Profile Subscribed is also the maximum QoS per PDPcontext to the associated APN. Subscribed Evolved ARP The SubscribedEvolved ARP for PDP contexts associated with the APN. VPLMN AddressAllowed Specifies per VPLMN whether the MS is allowed to use the APN inthe domain of the HPLMN only, or additionally the APN in the domain ofthe VPLMN. PDP/EPS Bearer context The charging characteristics of thisPDP/EPS Bearer context, Charging Characteristics e.g. normal, prepaid,flat-rate, and/or hot billing. EPS subscribed QoS The EPS bearer levelQoS parameter values for that APN's profile default bearer (QCI and ARP)APN-AMBR The maximum aggregated uplink and downlink MBR values to beshared across all Non-GBR EPS bearers, which are established for thisAPN. P-GW/GGSN address The address currently used for the P-GW/GGSNsupporting this APN

The contents, i.e. the fields, of the first and second sets I, II ofsubscriber data may be predefined in advance by e.g. the networkoperator. The contents of the first and second sets I, II may also bedetermined upon a trigger to transfer subscription data to the attachcontrol node 10, dependent e.g. on a precondition. For example, if thestorage 12 of the attach control node 10 is almost full, a very limitedfirst set I of subscription data may be stored in the attach controlnode 10. On the other hand, if there is an indication that sufficientstorage capacity is available at storage 12, an extensive set ofsubscription data may be stored in the attach control node 10. Otherpreconditions may also determine the contents of the first and secondset I, II of subscription data, such as e.g. based on what was agreedbetween the network operator and the owner of the UE 3 (such informatione.g. being stored in the subscriber data system).

FIGS. 5A-5C are sequence diagrams for a 2G/3G telecommunications system1 illustrating various embodiments of establishing a partial attachstate for a UE in the telecommunications network. Steps similar to thesteps shown in FIG. 2A have identical reference numbers. In each of theembodiments, the HLR has or receives a partial transfer indicationtriggering the HLR to transfer only the first set I of subscription datato the SGSN.

In the sequence diagram of FIG. 5A, steps (i)-(iii) are identical tosteps (i)-(iii) of FIG. 2A. However, the HLR contains an indication thatthe UE 3 has a partial attach subscription. As a consequence of thisindication, in step (iv) the controller CTRL of the HLR instructsprocessor uP to only transmit the first set I of subscription data tothe SGSN. The SGSN therefore only receives the first set I ofsubscription data and stores this first set I in storage 12. The currentstate of the UE may then be set in the HLR to partially attached. Step(v) now indicates to the HLR that the first set has been receivedsuccessfully.

In the sequence diagram of FIG. 5B, the SGSN receives an attach requestfrom UE 3 in step (i) and then determines that it can only accommodate apartial attach state for the UE. The determination to request a partialattach can be done on the basis of a precondition, e.g. the current loadexperienced by the SGSN (i.e. the number of attach requests) or thestate (e.g. the free capacity) of the storage 12. Accordingly, in step(iii), the SGSN requests the HLR for a partial attachment of UE 3.Optionally, the HLR has an indication that partial attach is allowed forUE 3. Optionally, the current state of the UE may then be set in the HLRto partially attached. Steps (iv)-(vii) are identical to thecorresponding steps in FIG. 5A.

In the sequence diagram of FIG. 5C, it is the UE 3 itself that requestsa partial attach. In step (i), the attach request contains an indicationthat only a partial attach is requested. The SGSN forwards the requestfrom UE 3 for a partial attach to the HLR. Again, optionally, the HLRhas an indication that partial attach is allowed for UE 3. Optionally,the current state of the UE may then be set in the HLR to partiallyattached. Steps (iv)-(vii) are identical to the corresponding steps inFIG. 5A.

Although only shown in FIG. 5C, the Attach accept of step (vii) in FIGS.5A-5C may contain information indicative for the UE 3 that a PDP contextcannot be established. As a consequence, the UE 3 may refrain fromtransmitting a PDP context Activation request as depicted in FIG. 2B.This may cause a further reduction of the load of the telecommunicationssystem 1.

In each of the embodiments of FIGS. 5A-5C, the HLR has or receives apartial transfer indication triggering the HLR to transfer only thefirst set I of subscription data to the SGSN. As mentioned previously,the first set of subscription data is insufficient for enablingestablishment of a communication session between the UE 3 and thetelecommunications system 1. This effect is illustrated in FIG. 6,wherein the Activation request for a PDP context from the UE 3, if sent,is rejected because the SGSN has only allowed a partial attach for theUE 3. The partial attach state of the SGSN for UE 3 may be implementedby an explicit indication in the SGSN or be implicit by the lack of thesecond set II of subscription data.

A similar effect may be obtained by transmitting the (complete set of)subscription data to the SGSN but only storing a first set of thesubscription data. This is illustrated in FIG. 5D.

Of course, information may be available in the telecommunications system1 for a UE 3 for which only the first set I of subscription data isavailable in the attach control node 10. Such information may e.g.originate from application server 2. In order to transfer suchinformation to the UE 3, a PDP context may be established between the UE3 and the telecommunications system 1. Such a PDP context can beinitiated by the UE 3 by sending an SMS message to the UE 3.

FIG. 7A provides an illustration of steps taken to transfer a message tothe UE 3 according to the prior art. It is assumed that the steps ofFIG. 2A have already been performed such that all subscription data arestored in the SGSN. An SMS Centre SMSC receives a mobile terminating SMSmessage MT SMS. In order to determine the SGSN under which UE 3 resides,the SMSC requests routing info from the HLR and receives the relevantSGSN from the HLR in response to the request as shown in FIG. 7A. Afterreceiving the indication of the SGSN, the SMS message is transferred viathe SGSN to the UE 3. The SGSN reports to the SMSC that the SMS messagehas been successfully delivered at the UE 3. The SMS message triggers UE3 to transmit a PDP Activation request message to the SGSN. Because theSGSN has available all subscriber data, the SGSN can process the PDPcontext Activation request in a manner as depicted in FIG. 2B.

It is noted that mechanisms other than SMS triggers via the packetswitched domain are known for triggering a UE to transmit a PDP contextactivation request, e.g. by using a cell broadcast, sending a triggerSMS via the circuit switched domain or by using unanswered circuitswitched calls.

In an embodiment of the disclosed method, the SGSN does not containsufficient subscriber data to establish a communication session with theUE 3 to transfer data. FIGS. 7B and 7C show embodiments to change thestate of the SGSN from partial attach to full attach in case of a dataavailability indication. This requires interaction between the SGSN andthe HLR to transfer the second set II of subscriber data to the SGSN.This interaction can be initiated by either the HLR or the SGSN.

In FIG. 7B, the HLR recognizes a sends routing info message as a triggerof a UE in state partially attach. The routing info changes the state ofthe UE in the HLR to “attach” and the HLR pushes the second set II ofsubscriber data to the SGSN (which may be followed by an acknowledgementback to the HLR). When the UE receives the SMS messages, it activates aPDP context, which is accepted by the SGSN now, as the SGSN has thecomplete subscriber data, as in FIG. 2B. It should be noted that the SMSmessage transfer can take place independent on the transmission andstorage of the second set II of subscription data.

In FIG. 7C, the SGSN recognizes the SMS message transfer as a trigger ofa UE 3 in state “partial attach”. The SGSN requests the HLR to transferthe second set II of subscriber data and, in response, the HLR sends thesecond set II of subscriber data to the SGSN. It should be noted thatthe SMS message transfer from the SGSN to the UE can take placeindependent on the storage of the second set II of subscription data inthe SGSN.

When network initiated communication for a UE 3 is rather frequent, theapproach of FIG. 7B or 7C results in a considerable amount ofinteractions with the HLR. Alternatively, the complete subscriber datais stored in the storage 12 of the SGSN. The second set II of subscriberdata in the storage 12 can be overwritten by other data (e.g. after acertain available resource threshold has been passed in the SGSN). Thefirst set I of subscriber data cannot be overwritten as long as the UE 3should be in a partial attach state. If the second set II of subscriberdata is overwritten, the second set II of subscriber data should beretrieved from the HLR (of HSS) again when a PDP context should beestablished. FIG. 8 is a schematic illustration of an attach controlnode containing a storage 12 with a part A that cannot be overwritten(i.e. the part with the first set I of subscriber data) and a part Bthat can be overwritten, if required.

Alternative triggers than a data availability indication fortransferring the second set of subscriber data to the SGSN have beencontemplated. The second set II of subscription data may be desired atthe attach control node 10 in response to a resource availabilityindication received from the attach control node 10 at the HLRindicating the availability of resources for containing the second setof subscription data in the attach control node. As an example, storagecapacity may be available in the storage 12. In this case, acommunication session may be established more quickly.

In yet another example, the second set II of subscription data may betransmitted to the attach control node 10 from the HLR at a predefinedtime or within a predefined time interval. This case is advantageous ifinformation is available within the telecommunications system 1 when aUE 3 desires to establish a connection with the telecommunicationssystem. Such information may e.g. be available from a contract betweenthe operator of the telecommunications system and the operator of theuser equipment. As an example, such a contract may determine the time atwhich or the time interval during which the UE 3 will or is allowed totransmit data.

After a period of time, the state for a UE 3 in the telecommunicationssystem 1 may return from attach to partial attach again, for example butnot limited to after the expiry of a timer, at the end of thecommunication session between the UE 3 and the telecommunicationsnetwork, after a decrease of free resources in the attach control nodeor after intervention via network management.

FIGS. 9A and 9B are sequence diagrams for a 2G/3G telecommunicationssystem illustrating return from the full attach state to a partialattach state.

In FIG. 9A, the SGSN receives the trigger for a transition back topartial attach. The SGSN removes the subscriber data of the second setII that is not required for a partial attach from memory storage 12.When there are activated PDP contexts for the UE 3, the transition topartial attach results in a network initiated PDP context deactivation.Optionally, the SGSN informs the HLR, which changes the UE state in theHLR to partial detach. Optionally, the SGSN informs the UE 3 on thetransition to partial attach. The SGSN can do this proactively in aseparate message directly following the transition or in the PDP contextdeactivation, or reactively, in the reject of a PDP activation requestby the UE.

In FIG. 9B, the HLR receives the trigger for a transition from fullattach back to partial attach. The HLR changes the UE state to partialattach and requests the SGSN to delete the second set II of subscriberdata that is not required for a partial attach. When there are activatedPDP contexts for the UE, the transition back to partial attach resultsin a network initiated PDP context deactivation. Again, optionally, theSGSN informs the UE 3 on the transition to partial detach. The SGSN cando this proactively in a separate message directly following thetransition or in the PDP context deactivation, or reactively, in thereject of a PDP activation request by the UE.

FIGS. 10A-10C are sequence diagrams for an LTE/EPS telecommunicationssystem illustrating various embodiments of establishing a partial attachstate for a UE 3. In each of the embodiments, a first set I ofsubscription data is transferred to the MME as opposed to the prior artcase as depicted in FIG. 2C. The steps are similar to the steps of FIGS.5A-5C, albeit between different entities MME (as an attach control node10, instead of the SGSN) and the HSS (as a subscriber database system11, instead of the HLR). As can be observed from the figures, steps (vi)and (vii) are configured to inform the UE 3 that only a partial attachhas been established. In this manner, UE 3 is e.g. informed that nodefault bearer has been established. If the UE 3 itself has requested apartial attach, the UE 3 may already be aware of the partial attach andthe confirmation from the telecommunications system 1 may be omitted.The method as described with reference to FIG. 5D can also beimplemented for a LTE/EPS system.

FIGS. 11A and 11B are sequence diagrams for an LTE/EPStelecommunications system illustrating embodiments for a transition froma partial attach to a complete attach state for a UE. With LTE thetransition from partial attach to full attach comprises a transfer ofthe complete subscriber data together with the creation of a defaultbearer that is initiated from the MME explicitly instead of a normaldefault bearer creation that is created implicitly at the attachprocedure. Alternatively, the MME sends a message to the UE, thatinstructs the UE to activate a default bearer. Exemplary implementationsare shown in FIG. 11A (for the case with a trigger for a transition toattach that is received at the MME, similarly to a trigger to the SGSNas depicted in and described with reference to FIG. 7C) and in FIG. 11B(for the case with a trigger for a transition to attach that is receivedat the HSS, similarly to a trigger to the HLR as depicted in anddescribed with reference to FIG. 7B). The message to inform the UE onthe transition to attach may be combined with the default bearercreation signaling in some implementations.

FIGS. 12A and 12B are sequence diagrams for an LTE/EPStelecommunications system illustrating embodiments for a transition froma complete attach state back to a partial attach state for a UE. In FIG.12A, the MME is triggered for a transition back to the partial attachstate (similarly to a trigger to the SGSN as depicted in and describedwith reference to FIG. 9A). In FIG. 12B, the HSS is triggered to returnthe UE to a partial attach state (similarly to a trigger to the HLR asdepicted in and described with reference to FIG. 9B). In addition, thedefault bearer is removed when the UE 3 returns to the partial attachstate.

It is noted that the method has been described in terms of steps to beperformed, but it is not to be construed that the steps described mustbe performed in the exact order described and/or one after another. Oneskilled in the art may envision to change the order of the steps and/orto perform steps in parallel to achieve equivalent technical results.

With some modifications, one skilled in the art may extend theembodiments described herein to other architectures, networks, ortechnologies.

Various embodiments of the invention may be implemented as a programproduct for use with a computer system or a processor, where theprogram(s) of the program product define functions of the embodiments(including the methods described herein). In one embodiment, theprogram(s) can be contained on a variety of non-transitorycomputer-readable storage media (generally referred to as “storage”),where, as used herein, the expression “non-transitory computer readablestorage media” comprises all computer-readable media, with the soleexception being a transitory, propagating signal. In another embodiment,the program(s) can be contained on a variety of transitorycomputer-readable storage media. Illustrative computer-readable storagemedia include, but are not limited to: (i) non-writable storage media(e.g., read-only memory devices within a computer such as CD-ROM disksreadable by a CD-ROM drive, ROM chips or any type of solid-statenon-volatile semiconductor memory) on which information is permanentlystored; and (ii) writable storage media (e.g., flash memory, floppydisks within a diskette drive or hard-disk drive or any type ofsolid-state random-access semiconductor memory) on which alterableinformation is stored.

It is to be understood that any feature described in relation to any oneembodiment may be used alone, or in combination with other featuresdescribed, and may also be used in combination with one or more featuresof any other of the embodiments, or any combination of any other of theembodiments. Moreover, the invention is not limited to the embodimentsdescribed above, which may be varied within the scope of theaccompanying claims.

The invention claimed is:
 1. A method for controlling an attach state ofa user equipment in an attach control node of a telecommunicationssystem further comprising a subscriber database containing subscriptiondata of the user equipment, the method comprising: receiving in a firsttransfer stage a first set of subscription data from the subscriberdatabase and storing the first set of subscription data in the attachcontrol node, wherein the first set of subscription data is insufficientfor enabling establishing a communication session between the userequipment and the telecommunications system, and wherein, if anauthentication step is required, authentication data are received in theattach control node prior to the receiving in the first transfer stage;if establishing a communication session is required between the userequipment and the telecommunications network, receiving in a secondtransfer stage following the first transfer stage at least one secondset of subscription data from the subscriber database in the attachcontrol node, and storing the second set of subscription data in theattach control node, wherein a combination of the first set ofsubscription data and the second set of subscription data is sufficientfor enabling establishing a communication session between the userequipment and the telecommunications network.
 2. The method according toclaim 1, wherein the first set of subscription data is free ofcommunication session management subscription data and comprises theNetwork Access Mode parameter.
 3. The method according to claim 1,wherein only the second set of the subscription data comprisescommunication session management subscription data.
 4. The methodaccording to claim 2, wherein the receiving and storage of the first setof subscription data comprises: transmitting a request from the attachcontrol node to the subscriber database in response to receiving anattach request from the user equipment at the attach control node, andreceiving only the first set of subscription data on the basis of apartial transfer indication associated with the user equipment in thesubscription database; transmitting a request from the attach controlnode to the subscriber database, the request containing a partialtransfer indication; and receiving subscriber data from the subscriberdatabase and storing only a first set of subscriber data from thereceived subscriber data in response to a partial attach stateindication in the attach control node.
 5. The method according to claim1, wherein the storage of the second set of subscription data istriggered by at least one of the following: a data availabilityindication in the telecommunications system indicating the availabilityof user data for the user equipment; a resource availability indicationtransmitted from the attach control node indicating the availability ofresources for containing the second set of subscription data in theattach control node; or expiration of a timer.
 6. The method accordingto claim 1, further comprising deleting from the combination of thefirst set of subscription data and the second set of subscription datathe at least one second set of subscription data at the attach controlnode after a precondition has been fulfilled and, if thetelecommunications system is an LTE telecommunications system, removinga default bearer for the user equipment.
 7. The method according toclaim 1, wherein the telecommunications system comprises an LTEtelecommunications system, further comprising: omitting establishing adefault bearer on a radio path between the user equipment and the LTEtelecommunications system prior to initiation of the second transferstage; providing the user equipment with information indicative ofnon-establishment of the default bearer prior to the initiation of thesecond transfer stage; and establishing the default bearer upon or afterinitiation of the second transfer stage by the attach control node.
 8. Anon-transitory computer-readable medium having instructions storedthereon that, upon execution by one or more processors of atelecommunications system comprising an attach control node and asubscriber database containing subscription data of a user equipment,cause the one or more processors to carry out operations including:receiving in a first transfer stage a first set of subscription datafrom the subscriber database and storing the first set of subscriptiondata in the attach control node, wherein the first set of subscriptiondata is insufficient for enabling establishing a communication sessionbetween the user equipment and the telecommunications system, andwherein, if an authentication step is required, authentication data arereceived in the attach control node prior to the receiving in the firsttransfer stage; if establishing a communication session is requiredbetween the user equipment and the telecommunications network, receivingin a second transfer stage following the first transfer stage at leastone second set of subscription data from the subscriber database in theattach control node, and storing the second set of subscription data inthe attach control node, wherein a combination of the first set ofsubscription data and the second set of subscription data is sufficientfor enabling establishing a communication session between the userequipment and the telecommunications network.
 9. A subscriber databasesystem configured for use in a telecommunications system, wherein thetelecommunications system comprises an attach control node, thesubscriber database system comprising: a subscriber database containingsubscription data of a user equipment; a processor having access toinstructions that when executed cause the database system to carry outoperations including: in a first transfer stage, providing to the attachcontrol node a first set of subscription data from the subscriberdatabase, wherein the first set of subscription data is insufficient forenabling establishing a communication session between the user equipmentand the telecommunications system, and wherein, if the attach controlreceived authentication data in an authentication step, the firsttransfer stage is carried out following the authentication step, ifestablishing a communication session is required between the userequipment and the telecommunications network, then in a second transferstage following the first transfer stage, providing to the attachcontrol node at least one second set of subscription data from thesubscriber database, wherein a combination of the first set ofsubscription data and the second set of subscription data is sufficientfor enabling establishing a communication session between the userequipment and the telecommunications network.
 10. A telecommunicationsnode configured for use in a telecommunications system, wherein thetelecommunications system comprises a subscriber database containingsubscription data of a user equipment, the telecommunications nodecomprising: a processor having access to instructions that when executedcause the telecommunications node to carry out operations including:receiving in a first transfer stage a first set of subscription datafrom the subscriber database and storing the first set of subscriptiondata in the telecommunications node, wherein the first set ofsubscription data is insufficient for enabling establishing acommunication session between the user equipment and thetelecommunications system, and wherein, if an authentication step isrequired, authentication data are received in the telecommunicationsnode prior to the receiving in the first transfer stage; if establishinga communication session is required between the user equipment and thetelecommunications network, receiving in a second transfer stagefollowing the first transfer stage at least one second set ofsubscription data from the subscriber database, and storing the secondset of subscription data in the telecommunications node, wherein acombination of the first set of subscription data and the second set ofsubscription data is sufficient for enabling establishing acommunication session between the user equipment and thetelecommunications network.
 11. The telecommunications node according toclaim 10, wherein the first set of subscription data is free ofcommunication session management subscription data and comprises theNetwork Access Mode parameter and wherein the second set of thesubscription data comprises communication session managementsubscription data.
 12. The telecommunications node according to claim11, wherein receiving and storing the first set of subscription datacomprises: transmitting a request from the telecommunications node tothe subscriber database in response to receiving an attach request fromthe user equipment at the telecommunications node, and receiving onlythe first set of subscription data on the basis of a partial transferindication associated with the user equipment in the subscriptiondatabase; transmitting a request from the telecommunications node to thesubscriber database, the request containing a partial transferindication; and receiving subscriber data from the subscriber databaseand storing only a first set of subscriber data from the receivedsubscriber data in response to a partial attach state indication in thetelecommunications node.
 13. The telecommunications node according toclaim 10, wherein storing the second set of subscription data istriggered by at least one of the following: a data availabilityindication in the telecommunications system indicating the availabilityof user data for the user equipment; a resource availability indicationtransmitted from the telecommunications node indicating the availabilityof resources for containing the second set of subscription data in thetelecommunications node; or expiration of a timer.
 14. Thetelecommunications node according to claim 10, wherein thetelecommunications node is further configured for deleting from thecombination of the first set of subscription data and the second set ofsubscription data the at least one second set of subscription data atthe telecommunications node after a precondition has been fulfilled and,if the telecommunications system is an LTE telecommunications system,removing a default bearer for the user equipment.
 15. Thetelecommunications node according to claim 10, wherein thetelecommunications system comprises an LTE telecommunication system andthe telecommunications node comprises an LTE telecommunications node,and wherein the the operations further include: omitting establishing adefault bearer on a radio path between the user equipment and the LTEtelecommunications system prior to initiation of the second transferstage; providing the user equipment with information indicative ofnon-establishment of the default bearer prior to the initiation of thesecond transfer stage; establishing the default bearer upon or afterinitiation of the second transfer stage by the attach control node. 16.A user equipment configured for use with a telecommunications node of atelecommunications system, wherein the telecommunications systemcomprises a subscriber database containing subscription data of the userequipment, wherein the telecommunications node is configured to: (i)receive in a first transfer stage a first set of subscription data fromthe subscriber database and store the first set of subscription data inthe telecommunications node, wherein the first set of subscription datais insufficient for enabling establishing a communication sessionbetween the user equipment and the telecommunications system; and (ii)if establishing a communication session is required between the userequipment and the telecommunications network, receive in a secondtransfer stage following the first transfer stage at least one secondset of subscription data from the subscriber database, and store thesecond set of subscription data in the telecommunications node, whereina combination of the first set of subscription data and the second setof subscription data is sufficient for enabling establishing acommunication session between the user equipment and thetelecommunications network and wherein the user equipment comprises: aprocessor having access to instructions that when executed cause theuser equipment to carry out operations including: receiving andprocessing at least one of: a partial subscription data transferindication indicative of storing only the first set of subscription datain the telecommunications node; or if the user equipment is an LTE typeuser equipment, a non-bearer establishment indication indicative ofomitting establishment of a default bearer on a radio path between theLTE type user equipment and the telecommunications node prior toinitiation of the second transfer stage being insufficient for enablingestablishment.
 17. The user equipment according to claim 16, wherein theoperations further include omitting requesting a communication sessionwith the telecommunications node when having processed at least one ofthe partial subscription data transfer indication and the non-bearerestablishment indication.